BitTorrent is an open protocol for sharing large files and filesets. It's super easy to use. BitTorrentDownloads are started just by clicking on small .torrent files or hyperlinks which are opened with your choice of BitTorrent client. Downloaders get pieces of the fileset from the original server, and from anyone else who is downloading. The more people there are downloading the same thing, the lower the burden on the central server, and the faster everyone's downloads get, due to sharing with each other. The more, the merrier!

Bram Cohen's official [BitTorrent] implementation. If you haven't tried it since the early days, you will be impressed. It has a nice GUI, distributed hash table tracking, queueing, global bandwidth adjustment, internationalization, and high performance. Open source. Runs on Windows, Mac OSX, Linux and Unix.

[TurboBT] - Windows GUI, Chinese as well as English. Reportedly goes easier on system resources.

[LimeWire]. The newest version (4.14+) includes support for bittorrent. It's designed to be as simple as possible, and doesn't contain all the features or controls other bittorrent clients have, but will get the job done just as quickly and easily. Open source. Runs on Windows, Mac OSX, Linux and Unix.

Some clients for Macintosh:

Bram Cohen's official [BitTorrent] implementation. If you haven't tried it since the early days, you will be impressed. It has a nice GUI, distributed hash table tracking, queueing, global bandwidth adjustment, internationalization, and high performance. Open source. Runs on Windows, Mac OSX, Linux and Unix.

Recommended:[Azureus] Java-based client. Available for multiple languages, and for multiple platforms (including Mac OS X). Built in tracker, the most feature rich of all the clients, everything adjustable, open source.

For Mac OSX, [Carrafix] can help manage bandwidth in conjunction with BT. Set the filter for all the ports BT uses (6881-6999).

[LimeWire]. The newest version (4.14+) includes support for bittorrent. It's designed to be as simple as possible, and doesn't contain all the features or controls other bittorrent clients have, but will get the job done just as quickly and easily. Open source. Runs on Windows, Mac OSX, Linux and Unix.

Some clients for Unix flavors:

Bram Cohen's official [BitTorrent] implementation. If you haven't tried it since the early days, you will be impressed. It has a nice GUI, distributed hash table tracking, queueing, global bandwidth adjustment, internationalization, and high performance. Open source. Runs on Windows, Mac OSX, Linux and Unix.

Recommended:[Azureus] Java-based client. Available for multiple languages, and for multiple platforms. Built in tracker, the most feature rich of all the clients, everything adjustable, open source.

Recommended:[ABC, Yet Another BitTorrent Client] for Windows and Linux (as of late 2003, the Linux version is less mature but very usable; see the [ABC FAQ] for details). ABC includes queuing of multiple torrents, global bandwidth adjustment, torrent creation. New, based on Shadow Client, under active development. Currently at version 2.6.5 or higher.

[LimeWire]. The newest version (4.14+) includes support for bittorrent. It's designed to be as simple as possible, and doesn't contain all the features or controls other bittorrent clients have, but will get the job done just as quickly and easily. Open source. Runs on Windows, Mac OSX, Linux and Unix.

[Trackpak] from the FileSoup community, reportedly sets everything you need up under Windows (webserver too? not sure).

[yaBTuc] - yet another BitTorrent upload center is a system to run your own bt-upload site. It combines suprnova (trackerless) with torrentbits (user-system, extensive information about the hosted torrents) - see homepage for more information.

Advice:

[LimeTracker] is a PHP tracker designed to run on commodity web hosting.

[BNBT] is a tracker program in development, with more features than the standard issue.